The Large Binocular Telescope

Introduction


The Large Binocular Telescope is maintained by the Large Binocular Telescope Observatory (LBTO) which itself is funded and maintained by the LBT consortium (LBTC). The LBTC has 5 partners, one of which is the German LBT Beteiligungsgesellschaft (LBTB). The LBTB holds 25% of the observing time at the LBT and is composed of the Max-Planck-Institute for Astronomy in Heidelberg, the Max-Planck-Institute for extraterrestrial physics in Garching, the Max-Planck-Institute for Radio Astronomy in Bonn, the Leibniz-Institute for astrophysics in Postdam and the Landessternwarte Heidelberg (LSW). At present, the LSW has a modest share of the observing time of about 5 nights per year. This includes guaranteed time as compensation for funding by the Federal Ministry of Education and Research (BMBF) to built instruments for the LBT.
The Large Binocular Telescope
The LBT at dusk. Credit: LBTO

The LBT is located on Mt. Graham at the Mount Graham National Observatory (MGIO, link) about 240km east of Tucson, Arizona at an altitude of 3200m. It is in operation 10 months per year and being closed most of July and August due to the monsoon season.

Instrumentation


The unique aspect of the LBT is twofold. First of all, it harbors two 8.4m mirrors on a common mount, which allow interferometric measurements with a spatial resolution of a 22m baseline. Secondly, it has modern state-of-the-art instruments available. Four pairs of basically identical wide-fields cameras, optical and near-infrared imager and multi-object spectropgraphs, as well as very-high resolution Echell spectrographs can be used. Complemented is the LBT by various interferometers. The near-infrared instruments can be used in combination with lasers for ground-layer adaptive optics correction over a large field of view or natural guide-star adaptive optics correction for highest spatial resolution.
The two LUCI instruments at the LBT
The two LUCI instruments at the LBT. Each instrument weighs about 3.3 metric tons and has a diametr of 1.5m. Credit: LBTO

Most of the instruments are delivered by the partners as inkind contribution to the project. The LBTB inkind contribution are the LUCI instruments, a pair of near-infrared images and multi-object spectrographs. The LSW is the PI institute of these instruments. See also the "press release by the University of Heidelberg"

Strategic importance of the LBT for the LSW

The LBT and its instrumentation is of strategic importance for the LSW. It allows to conduct observations with an 8m class telescope on the northern sky and is in support of the major scientific working areas at the LSW - the characterization of extrasolar planets, active galactic nuclei and galactic archeology. Some examples:
Direct imaging of exoplanets with the LBT Spectrum of the star Kepler 555 hosting at least 5 planets
Left) Direct image of extrasolar planets orbiting HR 8799 Credit: A.-L. Maire, LBTO. Right) A very high resolution spectrum of Kepler 444. This star hosts at least 5 extrasolar planets. Credit: K. Strassmeier, AIP.

Dual AGN candidate SDSS J085837.53+182221.6 Dual AGN candidate 3C 294
Left) NIR/optical images and optical spectra of a candidate harboring two active galactic nuclei. Apparently this systems harbors only one AGN which is inbetween the prominent optical components and belongs to the central feature in the left NIR-image. Credit: J. Heidt, LSW. Right) Adaptive optics aided NIR-image of the high-redshift radio galaxy 3C 294. The source breaks into three components two of which may harbor an active galactic nucleus. Credit: J. Heidt, LSW.

Comparison of LBT NIR and HST-image of M5
Comparison of a LBT adaptice optics aided NIR-image of the globular cluster Messier 5 to the same field observed by the Hubble Space Telescope. The LBT-image is much sharper. Globular clusters are prime targets for Galactic Archeology studies. Galactic Archeology is supported by the Collaborative Research Center SFB 881 "The Milky Way System". Credit: W. Seifert, LSW.